#include "gnuplot_plugin.h"
#include <math.h>
#include <gsl/gsl_sf_bessel.h>

DLLEXPORT struct value Jn(int nargs, struct value *arg, void *p){

  struct value r;
  double x;
  int n;
  
  RETURN_ERROR_IF_WRONG_NARGS(r, nargs, 2);
  RETURN_ERROR_IF_NONNUMERIC(r, arg[0]);
  RETURN_ERROR_IF_NONNUMERIC(r, arg[1]);
  
  r.type = CMPLX;
  n = IVAL(arg[0]);
  x = RVAL(arg[1]);
  
  r.v.cmplx_val.real = gsl_sf_bessel_Jn(n, x);
  r.v.cmplx_val.imag = 0.0;
  
  return r;
}